In an incredible feat of engineering, NASA has once again landed a rover on the surface of Mars. The Perseverance rover touched down safely today, Thursday, February 18, after a picture-perfect landing sequence.
The rover has spent the last seven months traveling to Mars after being launched in July last year. Having traveled through space, it began its descent sequence by jettisoning its cruise stage. That left just the aeroshell which protects the rover as it moves through the atmosphere.
The really tricky part of a Mars landing is the communication delay. Because Mars is so far away, it takes up to 20 minutes for communications from there to reach Earth, depending on its current distance. At the time of the landing, Mars was 127 million miles away and the delay was around 11 minutes.
That meant the engineers had to pre-program the spacecraft to land itself, as they could not make any adjustments during the landing phase. That’s why the period between entering the atmosphere and landing safely is referred to as the “seven minutes of terror.”
The spacecraft entered the atmosphere, which slowed it down from 12,500 mph, then it deployed a parachute to slow it further to 900 mph. In the last 20 seconds before landing, a jet pack with eight engines pointed downward fired to slow it even more, before the rover was lowered on cables to gently touch down on the surface.
The rover (and the engineers) made it through this tricky sequence successfully, and Perseverance touched down at 3:55 p.m. ET. The landing was helped by a new system called Terrain Relative Navigation, in which the spacecraft’s cameras captured images of the surface as it approached, which it compared with onboard maps to identify potential hazards like large rocks or sand dunes. That allows the craft to select the safest area for landing.
The team were even able to receive first images from the rover’s engineering cameras, showing the shadow of the rover in the Martian regolith.
Perseverance can now begin its mission of searching for evidence of ancient life on Mars. Although Mars today is dry and lifeless, at one point in its history it had large amounts of liquid water on its surface. That means that microscopic life might possibly have evolved there. So Perseverance is landing in an area called the Jezero Crater, which was once full of water and could have provided a hospitable environment for life, to investigate.
The rover also has a sidekick in the form of the Ingenuity helicopter, a tiny lighter-than-air craft that will be the first to fly on another planet. That will be taking test flights later in the mission.
Now, the engineers at NASA will begin checking on the health of the rover and making sure everything is working as expected. There should be an update available on the rover’s status by tomorrow, Friday, February 19.
